1. Field of the Invention
The present invention relates to the general area of computer user interface, and is particularly directed to a control window providing selection options and display of multiple selection levels.
2. Description of Related Art
"Menus" are the format used in computing environments for displaying to the user, in the form of prompts, the choices available to select and implement a computer task.
In order to make user interfaces, such as menus, widely useable, it is quite important that the prompts displayed are accessible to the user, that is, the user can easily recognize the nature of the prompts and work with them. Displaying obscure prompts or cluttering a menu presentation simply confuses the user and reduces the usability of the computer application.
Thus, where the choice set in a menu is too large to display at once, the menu is generally subdivided into a logically structured hierarchy that the user passes through by making selections at each level of the hierarchy and putting in place a complete set of command parameters for the computer's performance of the desired task.
For further clarity of presentation, it is usually provided that the selection of an option at one level determines the displayed range of options for subsequent (lower) levels in the menu hierarchy.
The forgoing leads to a common problem that arises in user interface design, namely the support of choice selection through the multiple levels or tiers of a hierarchical menu structure, especially where the range of choices available at one level is dependent on the selections made at a previous or higher level.
A hierarchical menu situation can arise in many different types of applications, from the systems analyst's implementation of a database search or object/class query, to the everyday user's start-up of a personal computer management program.
For example, a query action may require the specification of several (possibly four or more) query field values, where each is chosen from a mutually exclusive set of values or choices. Furthermore, selection of the first value may change the available set for the second value, and so on through to the last level or tier, creating the effect of hierarchical levels through which the user must navigate while making selections at each level that will affect the choices available at subsequent levels. The query action will be implemented only after the value for the final level has been selected.
A somewhat similar situation can be faced by the everyday PC user in accessing a simple personal computer management program, such as a word processing program. The user may be faced with a series of menus each displaying several options, where the choice in each menu can determine the range of choices available in the menu at the next level.
In all of these applications, one traditional format for presenting the choices to the user is as a cascade of menus, each menu displaying only the choices available at that level. Once the choice is made, the menu and its selection disappear from view to be replaced by the menu listing the possible selections for the next level in descending through the levels of the menu selection. Thus, the user has no visual record of menu selections from previous higher levels and cannot easily alter an inappropriate earlier menu selection without passing through each earlier menu in the cascade in order to locate the selection now sought to be corrected.
Proposed methods for simplifying hierarchical selections and providing the user with ready access to earlier selections employ multiple listboxes. A single listbox is provided for every level of menu selection listing all possible options. In one format, the listboxes are "tiled" in descending order from one side to the other on a laterally scrolled display. However, as all permutations of menu level selections must be displayed simultaneously on the multiple listboxes, the number of menu level selections or the complexity of each menu level is necessarily determined by the display size.
In a second format, the multiple listboxes are displayed in offset overlay (as multiple "windows"), permitting the user to bring the list box of an earlier selection level to the foreground (by clicking the mouse on it) for review or change. Again, however, screen size, along with the desire to avoid undue clutter in presentation, limits the hierarchical depth and individual list box length (or range of options) for which this style of interface is viable.
A similar approach to that of multiple listboxes is taken in U.S. Pat. No. 5,179,653 to Fuller. In this menu system, pushbuttons for three selection levels of a menu system are displayed simultaneously around the periphery of a graphics data work area on a display screen. Again, the display size is a limiting factor in the number of menu selection levels that may be presented, and of the complexity at each level. In Fuller, it is specifically disclosed that the labelling on the pushbuttons at the second and third descending levels are generic in nature to increase the range of options. However, use of generic labelling limits the usability of this menu display to expert users.